Niche Models Research Articles

A historical stepping-stone path for an island-colonizing cactus across a submerged "bridge" archipelago.

Here we use population genomic data (ddRAD-Seq) and ecological niche modeling to test biogeographic hypotheses for the divergence of the island-endemic cactus species Cereus insularis Hemsl. (Cereeae; Cactaceae) from its sister species C. fernambucensis Lem. The Cereus insularis grows in the Fernando de Noronha Islands (FNI), a Neotropical archipelago located 350 km off the Brazilian Atlantic Forest (BAF) coast. Phylogeographic reconstructions support a northward expansion by the common ancestor of C. insularis and C. fernambucensis along the mainland BAF coast, with C. insularis diverging from the widespread mainland taxon C. fernambucensis after colonizing FNI in the late Pleistocene. The morphologically distinct C. insularis is monophyletic and nested within C. fernambucensis, as expected from a progenitor-derivative speciation model. We tested alternative biogeographic and demographic hypotheses for the colonization of the FNI using Approximate Bayesian Computation. We found the greatest support for a stepping-stone path that emerged during periods of decreased sea level (the "bridge" hypothesis), in congruence with historical ecological niche modeling that shows highly suitable habitats on stepping-stone islands during glacial periods. The outlier analyses reveal signatures of selection in C. insularis, suggesting a putative role of adaptation driving rapid anagenic differentiation of this species in FNI.

Phenotypic plasticity in tropical butterflies is linked to climatic seasonality on a macroevolutionary scale.

Phenotypic plasticity can be adaptive in fluctuating environments by providing rapid environment-phenotype matching and this applies particularly in seasonal environments. African Bicyclus butterflies have repeatedly colonized seasonal savannahs from ancestral forests around the late Miocene, and many species now exhibit seasonal polyphenism. On a macroevolutionary scale, it can be expected that savannah species will exhibit higher plasticity because of experiencing stronger environmental seasonality than forest species. We quantified seasonality using environmental niche modeling and surveyed the degree of plasticity in a key wing pattern element (eyespot size) using museum specimens. We showed that species occurring in highly seasonal environments display strong plasticity, while species in less seasonal or aseasonal environments exhibit surprisingly variable degrees of plasticity, including strong to no plasticity. Furthermore, eyespot size plasticity has a moderate phylogenetic signal and the ancestral Bicyclus likely exhibited some degree of plasticity. We propose hypotheses to explain the range of plasticity patterns seen in less seasonal environments and generate testable predictions for the evolution of plasticity in Bicyclus. Our study provides one of the most compelling cases showing links between seasonality and phenotypic plasticity on a macroevolutionary scale and the potential role of plasticity in facilitating the colonization of novel environments.

Predicting the global potential distribution of Bursaphelenchus xylophilus using an ecological niche model: expansion trend and the main driving factors.

Bursaphelenchus xylophilus (Steiner&Buhrer) Nickle is a global quarantine pest that causes devastating mortality in pine species. The rapid and uncontrollable parasitic spread of this organism results in substantial economic losses to pine forests annually. In this study, we used the MaxEnt model and GIS software ArcGIS10.8 to predict the distribution of B. xylophilus based on collected distribution points and 19 environmental variables (with a correlation coefficient of|R| > 0.8) for the contemporary period (1970-2000), 2041-2060 (2050s), 2061-2080 (2070s), and 2081-2100 (2090s) under four shared socioeconomic pathways (SSPs). We conducted a comprehensive analysis of the key environmental factors affecting the geographical distribution of B. xylophilus and suitable distribution areas. Our results indicate that in current prediction maps B. xylophilus had potential suitable habitats in all continents except Antarctica, with East Asia being the region with the most highly suitable areas and the most serious epidemic area currently. Precipitation of the warmest quarter, temperature seasonality, precipitation of the wettest month, and maximum temperature of the warmest month were identified as key environmental variables that determine the distribution of B. xylophilus. Under future climatic conditions, the potential geographic distribution of B. xylophilus will expand relative to current conditions. In particular, under the SSP5-8.5 scenario in 2081-2100, suitable areas will expand to higher latitudes, and there will be significant changes in suitable areas in Europe, East Asia, and North America. These findings are crucial for future prevention and control management and monitoring.

Coexistence, resource partitioning, and fisheries management: A tale of two mesopredators in equatorial waters.

Rock hind (Epinephelus adscensionis) and spotted moray (Gymnothorax moringa) are ubiquitous mesopredators that co-occur in the nearshore waters of Ascension Island in the South Atlantic Ocean, where they have significant cultural and subsistence value, but management of their non-commercial take is limited. This isolated volcanic system is home to high biomass and low species diversity, which poses two key questions: How can two mesopredators that perform similar ecological roles coexist? And if these two species are so ecologically similar, can they be managed using the same approach? Here, we combined acoustic telemetry, stomach content analysis, and stable isotope analysis to (i) explore space use and diet choices within and between these two species and (ii) to assess appropriate species-specific management options. Although rock hind had high residency and small calculated home ranges (0.0001-0.3114 km2), spotted moray exhibited shorter periods of residency (<3 months) before exiting the array. Vertical space use differed significantly across the 20-month tracking period, with individual differences in vertical space observed for both species. A hierarchical generalized additive model using 12-h averaged depth data identified that rock hind occurred lower in the water column than spotted moray, with both species occupying moderately deeper depths at night versus day (+1.6% relative depth). Spotted moray depth was also significantly predicted by lunar illumination. Aggregating samples by species and tissue type, Bayesian ecological niche modeling identified a 53.14%-54.15% and 78.02%-97.08% probability of niche overlap from fin clip and white muscle, respectively, whereas limited stomach content data indicated a preference for piscivorous prey. Variability in niche breadth between years suggests these species may exploit a range of prey items over time. These findings indicate that although these two species perform a similar ecological role by feeding on prey occupying the same trophic levels, subtle differences in movement behaviors between them suggest a one-rule-fits-all management approach is not likely the most effective option.

Poleward migration of tropical corals inhibited by future trends of seawater temperature and calcium carbonate (CaCO3) saturation

Poleward range expansion of marine organisms is commonly attributed to anthropogenic ocean warming. However, the extent to which a single species can migrate poleward remains unclear. In this study, we used molecular data to examine the current distribution of the Pocillopora damicornis species complex in Taiwan waters and applied niche modeling to predict its potential range through the end of the 21st Century. The P. damicornis species complex is widespread across shallow, tropical and subtropical waters of the Indo-Pacific regions. Our results revealed that populations from subtropical nonreefal coral communities are P. damicornis, whose native geographical ranges are approximately between 23°N and 35°N. In contrast, those from tropical reefs are P. acuta. Our analysis of 50 environmental data layers demonstrated that the concentrations of CaCO3 polymorphs had the greatest contributions to the distributions of the two species. Future projections under intermediate shared socioeconomic pathways (SSP) 2–4.5 and very high (SSP5–8.5) scenarios of greenhouse gas emissions showed that while sea surface temperature (SST) isotherms would shift northwards, saturation isolines of two CaCO3 polymorphs, calcite (Ωcal) and aragonite (Ωarag), would shift southwards by 2100. Subsequent predictions of future suitable habitats under those conditions indicated that distinct delimitation of geographical ranges for the two species would persist, and neither would extend beyond its native geographical zones, indicating that tropical Taiwan waters are the northern limit for P. acuta. In contrast, subtropical waters are the southern limit for P. damicornis. We concluded that the decline in CaCO3 saturation would make high latitudes less inhabitable, which could be one of the boundary elements that limit poleward range expansion driven by rising SSTs and preserve the latitudinal diversity gradient (LDG) on Earth. Consequently, poleward migration of tropical reef corals to cope with warming oceans should be reevaluated.

Proteomic analysis reveals a potential role for extracellular vesicles within the erythroblastic island niche.

Introduction: Erythroblastic island (EBI) macrophages play an essential role in the production and maturation of the vast numbers of red blood cells (RBCs) that are produced throughout life. Their location within the bone marrow makes it difficult to study the cellular and molecular interactions associated with their action so we have used an in vitro model of the EBI niche using macrophages derived from human induced pluripotent stem cells (hiPSCs). We previously demonstrated that the activation of the transcription factor KLF1 enhanced the activity of hiPSC-derived EBI macrophages. Methods: To elucidate the mechanisms associated with EBI-like activity we carried out a quantitative proteomic analysis and assessed the role of extracellular vesicles using Nanosight Tracking analyses and media filtration. Results and Discussion: Gene ontology analysis showed that many of the proteins upregulated by KLF1 were protein-binding factors, some of which were associated with the cell membrane or extracellular vesicles We demonstrated that filtration of macrophage-conditioned media resulted in a reduction in the supportive effects on erythroid cell viability and maturation implying a role for extracellular vesicles but this was not KLF1 dependent. Pathway analyses of the proteomic data revealed that proteins upregulated by KLF1 were associated with the citric acid cycle, pyruvate metabolism and ATP synthesis indicating that KLF1-activated macrophages had a metabolic profile comparable to a pro-reparative phenotype. This study has generated a proteomic dataset that could provide new insights into the role of macrophages within the EBI niche and has indicated a potential role for extracellular vesicles in the differentiation and maturation of RBCs in vitro. Further research will aid in the production of RBCs in vitro for use in disease modelling and cell therapy.

Presence of the crab-eating fox Cerdocyon thous in La Rioja, Argentina, and implications for its geographic and environmental niche modeling

Abstract The crab-eating fox Cerdocyon thous is one of South America’s most common species of canids; its generalist habits and plasticity allowed the species to adapt to numerous habitats and human presence. In 2020, we registered a specimen of C. thous on a trap camera placed in the vicinity of the Huaco River in La Rioja Province, Argentina. This record was the starting point for evaluating past and present environmental niche models (ENMs) of the species throughout their entire distribution in South America. ENMs models suggest that the presence of C. thous in La Rioja has low suitability values and suggest that we may be facing a sink population scenario due to the low frequency of records in the province. Also, the model indicated that the parameters delimiting the areas with the highest suitability values are related to temperature, isothermality, and precipitation. Long-term studies in the region are needed to determine the population dynamics of C. thous in La Rioja.

Phenotypic and genetic divergence in a cold‐adapted grasshopper may lead to lineage‐specific responses to rapid climate change

AbstractAimSpecies responses to global warming will depend on intraspecific diversity, yet studies of factors governing biogeographic patterns of variability are scarce. Here, we investigate the evolutionary processes underlying genetic and phenotypic diversity in the flightless and cold‐adapted grasshopper Sigaus piliferus, and project its suitable space in time.LocationTe Ika‐a‐Māui Aotearoa—North Island of New Zealand.MethodsWe used mitochondrial sequences to investigate population connectivity and demographic trends using phylogeographic tools and neutrality statistics. Metric data were used to document phenotypic variation using naïve clustering. We used niche metrics to assess intraspecific niche variation, and niche modelling to investigate suitability under past and future scenarios. Multiple matrix regressions with randomization explored the processes contributing to phenotypic differentiation among grasshopper populations.ResultsNiche models and demographic analyses suggest suitable space for this grasshopper was more restricted during glacial than interglacial stages. Genealogical relationships among ND2 haplotypes revealed a deep north–south split partly concordant with phenotypic and niche variation, suggesting two ecotypes that have mixed during recolonisation of the central volcanic region. Multiple matrix regressions with randomization indicate a link between climate and phenotypic differentiation inferred from leg and pronotum dimensions but not pronotum shape. Niche projections predict severe habitat reduction due to climate warming.Main conclusionsThe current distribution and intraspecific diversity of S. piliferus reflect complex biogeographical scenarios consistent with Quaternary climates and volcanism. Phenotypic divergence appears adaptive. Current levels of genetic and phenotypic variation suggest adaptive potential, yet the pace of anthropogenic warming over the next 50 years could result in small populations that may collapse before adapting. Differences in niche features between diverging intraspecific lineages suggest distinct responses to climate change, and this has implications for prioritising conservation actions and management strategies.

The integration of whole‐genome resequencing and ecological niche modelling to conserve profiles of local adaptation

AbstractBackgroundEcological and genomic attributes of populations can provide two orthologous perspectives on the biological profiles associated with local adaptation. The ability of organisms to track suitable habitats (ecological adaptability) and of populations to shift allele frequencies (adaptive potential) are prerequisite for population sustainability.AimsMany contemporary populations are threatened by habitat loss (ecological vulnerability) and a lack of adaptive potential (evolutionary vulnerability). Technical advances provide new opportunities to address these challenges in biological conservation: Future habitat shifts can be predicted by ecological niche modelling and adaptive genetic diversity can be discerned using genome sequence data. Together, these two approaches illuminate the local adaptation profile and help identify the environmental and genomic conditions that should maximize evolutionary fitness.Materials and MethodsHere, we reviewed the primary literature to identify key studies that utilize both whole‐genome resequencing (WGR) and ecological niche modelling (ENM) in an effort to envisage future research directions that may benefit conservation efforts.ResultsWe identified ways to integrate different approaches, such as ENM‐informed adaptive genomics and adaptive genomics‐informed ENMs, that can be used to delineate and conserve local adaptation profiles.DiscussionIntegrative approaches can identify adaptive characteristics, vulnerable populations subject to environmental changes, and the patterns of local adaptation from geographic and genomic analyses. We discuss future research directions, limitations and their potential solutions with suggestions for collaborative workflows.ConclusionThe integration of WGR and ENM is promising with their continuous advancement. An integrative approach can be used to evaluate eco‐evolutionary attributes, at both organismal and molecular levels, that can be used to help conserve local adaptation profiles.

Projections of Aedes and Culex mosquitoes across North and South America in response to climate change

IntroductionClimate and land use change may cause the geographical range of mosquitoes to expand, shift, or contract, ultimately changing what communities are at risk for contracting mosquito-borne diseases. Across North and South America, mosquitoes from the Aedes and Culex genera are vectors for numerous diseases, including chikungunya, dengue, various equine encephalitis viruses, Saint Louis encephalitis virus, West Nile virus, yellow fever virus, and Zika virus. The goal of our study was to project the geographical distributions of important mosquito vectors across North and South America in response to climate change, which is important to inform public health planning. MethodsWe used an ecological niche model and future projections of climate and land use to project the geographical ranges of two Aedes species (Ae. aegypti, Ae. albopictus) and seven Culex species (Cx. erraticus, Cx. nigripalpus, Cx. pipiens, Cx. quinquefasciatus, Cx. restuans, Cx. salinarius, Cx. tarsalis) over North and South America in response to both a high (Shared Socioeconomic Pathway [SSP] 5, Representative Concentration Pathway [RCP] 8.5) and moderate (SSP2 RCP4.5) climate warming scenario through years 2050 and 2090. ResultsFor SSP5 RCP8.5, six species (Ae. aegypti, Ae. albopictus, Cx. erraticus, Cx. nigripalpus, Cx. quinquefasciatus, Cx. restuans) are projected to expand in geographical range, two species (Cx. pipiens, Cx. tarsalis) are projected to shift in geographical range, and one species (Cx. salinarius) is projected to nearly remain the same. Five species (Ae. aegypti, Ae. albopictus, Cx. erraticus, Cx. nigripalpus, Cx. quinquefasciatus) show the largest increase in high habitat suitability (>0.5 on a 0–1 scale) for SSP5 RCP8.5, three species (Cx. pipiens, Cx. restuans, Cx. tarsalis) show the largest increase for SSP2 RCP4.5, and one species (Cx. salinarius) shows a relatively small decrease in response to both scenarios. ConclusionsWe found that all nine species responded resiliently to climate change under both the high and moderate climate warming scenario, suggesting mosquito-borne disease is likely to be a continued threat in response to climate change. The projected geographical ranges can be used to inform disease risk analyses and mitigation strategies in response to climate change.

Rethinking ecological niches and geographic distributions in face of pervasive human influence in the Anthropocene.

Species are distributed in predictable ways in geographic spaces. The three principal factors that determine geographic distributions of species are biotic interactions (B), abiotic conditions (A), and dispersal ability or mobility (M). A species is expected to be present in areas that are accessible to it and that contain suitable sets of abiotic and biotic conditions for it to persist. A species' probability of presence can be quantified as a combination of responses to B, A, and M via ecological niche modeling (ENM; also frequently referred to as species distribution modeling or SDM). This analytical approach has been used broadly in ecology and biogeography, as well as in conservation planning and decision-making, but commonly in the context of 'natural' settings. However, it is increasingly recognized that human impacts, including changes in climate, land cover, and ecosystem function, greatly influence species' geographic ranges. In this light, historical distinctions between natural and anthropogenic factors have become blurred, and a coupled human-natural landscape is recognized as the new norm. Therefore, B, A, and M (BAM) factors need to be reconsidered to understand and quantify species' distributions in a world with a pervasive signature of human impacts. Here, we present a framework, termed human-influenced BAM (Hi-BAM, for distributional ecology that (i) conceptualizes human impacts in the form of six drivers, and (ii) synthesizes previous studies to show how each driver modifies the natural BAM and species' distributions. Given the importance and prevalence of human impacts on species distributions globally, we also discuss implications of this framework for ENM/SDM methods, and explore strategies by which to incorporate increasing human impacts in the methodology. Human impacts are redefining biogeographic patterns; as such, future studies should incorporate signals of human impacts integrally in modeling and forecasting species' distributions.

Bears into the Niche-Space: Phylogeography and Phyloclimatic Model of the Family Ursidae

Assessing niche evolution remains an open question and an actively developing area of study. The family Ursidae consists of eight extant species for which, despite being the most studied family of carnivores, little is known about the influence of climate on their evolutionary history and diversification. We evaluated their evolutionary patterns based on a combined phylogeography and niche modeling approach. We used complete mitogenomes, estimated divergence times, generated ecological niche models and applied a phyloclimatic model to determine the species evolutionary and diversification patterns associated with their respective environmental niches. We inferred the family evolutionary path along the environmental conditions of maximum temperature and minimum precipitation, from around 20 million years ago to the present. Our findings show that the phyloclimatic niches of the bear species occupy most of the environmental space available on the planet, except for the most extreme warm conditions, in accordance with the wide geographic distribution of Ursidae. Moreover, some species exhibit broader environmental niches than others, and in some cases, they explore precipitation axes more extensively than temperature axes or vice versa, suggesting that not all species are equally adaptable to these variables. We were able to elucidate potential patterns of niche conservatism and evolution, as well as niche overlapping, suggesting interspecific competitive exclusion between some of the bear species. We present valuable insights into the ecological and evolutionary processes driving the diversification and distribution of the Ursidae. Our approach also provides essential information for guiding effective conservation strategies, particularly in terms of distribution limits in the face of climate change.

Range-Wide Phylogeography and Ecological Niche Modeling Provide Insights into the Evolutionary History of the Mongolian Racerunner (Eremias argus) in Northeast Asia.

The Mongolian racerunner, Eremias argus, is a small lizard endemic to Northeast Asia that can serve as an excellent model for investigating how geography and past climate change have jointly influenced the evolution of biodiversity in this region. To elucidate the processes underlying its diversification and demography, we reconstructed the range-wide phylogeographic pattern and evolutionary trajectory, using phylogenetic, population genetic, landscape genetic, Bayesian phylogeographic reconstruction and ecological niche modeling approaches. Phylogenetic analyses of the mtDNA cyt b gene revealed eight lineages that were unbounded by geographic region. The genetic structure of E. argus was mainly determined by geographic distance. Divergence dating indicated that E. argus and E. brenchleyi diverged during the Mid-Pliocene Warm Period. E. argus was estimated to have coalesced at~0.4351 Ma (Marine Isotope Stage 19). Bayesian phylogeographic diffusion analysis revealed out-of-Inner Mongolia and rapid colonization events from the end of the Last Interglacial to the Last Glacial Maximum, which is consistent with the expanded suitable range of the Last Glacial Maximum. Pre-Last Glacial Maximum growth of population is presented for most lineages of E. argus. The Glacial Maximum contraction model and the previous multiple glacial refugia hypotheses are rejected. This may be due to an increase in the amount of climatically favorable habitats in Northeast Asia. Furthermore, E. argus barbouri most likely represents an invalid taxon. The present study is the first to report a range-wide phylogeography of reptiles over such a large region in Northeast Asia. Our results make a significant contribution towards understanding the biogeography of the entire Northeast Asia.

Collective effects of rising average temperatures and heat events on oviparous embryos.

Survival of the immobile embryo in response to rising temperature is important to determine a species' vulnerability to climate change. However, the collective effects of 2 key thermal characteristics associated with climate change (i.e., rising average temperature and acute heat events) on embryonic survival remain largely unexplored. We used empirical measurements and niche modeling to investigate how chronic and acute heat stress independently and collectively influence the embryonic survival of lizards across latitudes. We collected and bred lizards from 5 latitudes and incubated their eggs across a range of temperatures to quantify population-specific responses to chronic and acute heat stress. Using an embryonic development model parameterized with measured embryonic heat tolerances, we further identified a collective impact of embryonic chronic and acute heat tolerances on embryonic survival. We also incorporated embryonic chronic and acute heat tolerance in hybrid species distribution models to determine species' range shifts under climate change. Embryos' tolerance of chronic heat (T-chronic) remained consistent across latitudes, whereas their tolerance of acute heat (T-acute) was higher at high latitudes than at low latitudes. Tolerance of acute heat exerted a more pronounced influence than tolerance of chronic heat. In species distribution models, climate change led to the most significant habitat loss for each population and species in its low-latitude distribution. Consequently, habitat for populations across all latitudes will shift toward high latitudes. Our study also highlights the importance of considering embryonic survival under chronic and acute heat stresses to predict species' vulnerability to climate change.

Prediction and validation of potential transmission risk of Dirofilaria spp. infection in Serbia and its projection to 2080.

Animal and human dirofilariosis is a vector-borne zoonotic disease, being one of the most important diseases in Europe. In Serbia, there are extensive studies reporting the presence of Dirofilaria immitis and D. repens, mainly in the north of the country, where the human population is concentrated and where there is a presence of culicid mosquitoes that transmit the disease. Ecological niche modeling (ENM) has proven to be a very good tool to predict the appearance of parasitosis in very diverse areas, with distant orography and climatologies at a local, continental, and global level. Taking these factors into account, the objective of this study was to develop an environmental model for Serbia that reflects the suitability of the ecological niche for the risk of infection with Dirofilaria spp. with which the predictive power of existing studies is improved. A wide set of variables related to the transmission of the parasite were used. The potential number of generations of D. immitis and the ecological niche modeling method (ENM) were used to estimate the potential distribution of suitable habitats for Culex pipiens. The highest probability of infection risk was located in the north of the country, and the lowest in the southern regions, where there is more orographic relief and less human activity. The model was corroborated with the location of D. immitis-infected dogs, with 89.28% of the country having a high probability of infection. In addition, it was observed that the percentage of territory with optimal habitat for Culex spp. will increase significantly between now and 2080. This new model can be used as a tool in the control and prevention of heartworm disease in Serbia, due to its high predictive power, and will serve to alert veterinary and health personnel of the presence of the disease in the animal and human population, respectively.

Spacial distribution and suitability for Panonychus ulmi (Tetranychidae) in Brazil

Predictive studies project the geographic distribution of species and can be used to infer climatic niches. However, only a few studies have been conducted on mites. This approach helps map areas with potential for the occurrence of endemic, threatened, or potentially invasive species. Panonychus ulmi (Tetranychidae) is of global economic importance, commonly associated with apple orchards and grapevines. Potential distribution modeling is used to predict areas with environmental suitability for the distribution of a species and/or group. Considering that predictive models on national or regional scales present better data reliability, the present study aimed to analyze the distribution of P. ulmi in Brazil through bioclimatic inferences. The presence of species, bioclimatic variables, and MaxEnt algorithm were used to define a predictive model. The median performance rate of the model was 0.992, indicating its robustness. The variable that made the greatest contribution to the model was the average temperature of the coldest quarter (Bio11). The predictive model of the ecological niche indicated that the southern region of Brazil is environmentally favorable for the adaptation of this mite. The data obtained helped us understand the geographical distribution of P. ulmi in Brazil, and climatically suitable areas for its occurrence were inferred. We believe that this tool can offer indirect assistance to the agricultural sector, especially the producers of apples and grapes in Brazil regarding the presence of P. ulmi.

Across two phylogeographic breaks: Quaternary evolutionary history of a mountain aspen (Populus rotundifolia) in the Hengduan Mountains

Biogeographical barriers to gene flow are central to plant phylogeography. In East Asia, plant distribution is greatly influenced by two phylogeographic breaks, the Mekong-Salween Divide and Tanaka-Kaiyong Line, however, few studies have investigated how these barriers affect the genetic diversity of species that are distributed across both. Here we used 14 microsatellite loci and four chloroplast DNA fragments to examine genetic diversity and distribution patterns of 49 populations of Populus rotundifolia, a species that spans both the Mekong-Salween Divide and the Tanaka-Kaiyong Line in southwestern China. Demographic and migration hypotheses were tested using coalescent-based approaches. Limited historical gene flow was observed between the western and eastern groups of P. rotundifolia, but substantial flow occurred across both the Mekong-Salween Divide and Tanaka-Kaiyong Line, manifesting in clear admixture and high genetic diversity in the central group. Wind-borne pollen and seeds may have facilitated the dispersal of P. rotundifolia following prevalent northwest winds in the spring. We also found that the Hengduan Mountains, where multiple genetic barriers were detected, acted on the whole as a barrier between the western and eastern groups of P. rotundifolia. Ecological niche modeling suggested that P. rotundifolia has undergone range expansion since the last glacial maximum, and demographic reconstruction indicated an earlier population expansion around 600 Ka. The phylogeographic pattern of P. rotundifolia reflects the interplay of biological traits, wind patterns, barriers, niche differentiation, and Quaternary climate history. This study emphasizes the need for multiple lines of evidence in understanding the Quaternary evolution of plants in topographically complex areas.

Distribution models in invasive plants with climatic niche expansion: a case study of Ulex europaeus L. in Colombian Andes

Invasive plants have a wide distribution worldwide. Their ability to adapt and colonize different climates is attributed to the phenotypic plasticity and the expansion of the climatic niche of the species. Simultaneously, their distribution patterns will be affected by climate change, creating or reducing the ideal areas for their establishment. We evaluated the current and potential distribution of Ulex europaeus L. in Colombia, under the global circulation models ACCESS-ESM1-5 and MIROC6 in two scenarios, for the years 2041–2060, taking into account its climate niche expansion. An ecological niche model was built for this purpose using Maxent algorithm of the KUENM, the records of the species in native and invasive condition from the GBIF portal, and records obtained through field trips and bioclimatic variables from Worldclim2 were used. Changes in potential distribution were analyzed with the Biomod2. A total of 1072 occurrence records were found for U. europaeus and 109 records were found in Colombia in the Cordillera Central and Oriental, where an expansion of the altitudinal range was evidenced from 2000 to 4052 m above sea level. Climate change models for Colombia showed that the creation of new areas for potential establishment is less than 1% and there is a reduction in potential distribution of 12 and 31% due to unsuitable climatic conditions that would affect their germination capacity. However, given its potential for adaptation, the invasions will persist in the new conditions and will continue their colonization process at higher altitudes where they find optimal temperatures for their germination and establishment.

Climate change will likely facilitate invasion of Asian orchid Eulophia graminea into new areas

Climate change plays an increasing role in the global biodiversity crisis. Alteration in local climatic conditions not only can negatively affect native biodiversity but also can accelerate the introduction and spread of invasive species. In this study the ecological niche modelling approach was used to evaluate possible changes in the distribution of suitable niches of invasive orchid Eulophia graminea within its native (Asia) and non-native geographical range (America, Australia). We mapped the current potential range of this species and analysed three various projections of future climate (for 2100) each with four different climate change scenarios (SSPs). Calculated niche overlap indexes indicated low similarity of niches occupied by native and invasive populations of E. graminea and Australian populations seem to be the most unique, while American and Asian groups share partially similar niches. The occurrence of the American population of E. graminea was correlated especially with the temperature seasonality, while the Asian and Australian populations with annual precipitation and precipitation of the wettest quarter. As indicated in our analyses within Asia and America, E. graminea does not occupy all climatically suitable niches. On the other hand, in Australia the species studied already occupies all appropriate niche space. Climate change will likely be favorable for species studied to expand its range if the biotic components of its niche space (e.g., mycorrhizal fungi) will respond similarly. The most significant range expansion is predicted to occur in Australia which is interesting considering the marginally suitable habitats that E. graminea currently occupies.

Genetically- and environmentally-dependent processes drive interspecific and intraspecific divergence in the Chinese relict endemic genus Dipteronia

China is a hotspot of relict plant species that were once widespread throughout the Northern Hemisphere. Recent research has demonstrated that the occurrence of long-term stable refugia in the mountainous regions of central and south-western China allowed their persistence through the late Neogene climate fluctuations. One of these relict lineages is Dipteronia, an oligotypic tree genus with a fossil record extending to the Paleocene. Here, we investigated the genetic variability, demographic dynamics and diversification patterns of the two currently recognized Dipteronia species (Dipteroniasinensis and D.dyeriana). Molecular data were obtained from 45 populations of Dipteronia by genotyping three cpDNA regions, two single copy nuclear genes and 15 simple sequence repeat loci. The genetic study was combined with niche comparison analyses on the environmental space, ecological niche modeling, and landscape connectivity analysis. We found that the two Dipteronia species have highly diverged both in genetic and ecological terms. Despite the incipient speciation processes that can be observed in D. sinensis, the occurrence of long-term stable refugia and, particularly, a dispersal corridor along Daba Shan-west Qinling, likely ensured its genetic and ecological integrity to date. Our study will not only help us to understand how populations of Dipteronia species responded to the tectonic and climatic changes of the Cenozoic, but also provide insight into how Arcto-Tertiary relict plants in East Asia survived, evolved, and diversified.